The actual laser Doppler velocity signal is always mixed with noise, which leads to great difficulty to find required Doppler frequency shift. In view of this problem, a wavelet threshold de-noising method is presented. According to the characteristics of the Doppler signal, the optimal effect of wavelet threshold de-noising is obtained when we choose proper wavelet decomposition layer number, wavelet basis function, threshold function and threshold estimation method. Results of Matlab simulations and experiments show that the wavelet threshold de-noising method can eliminate the noise in Doppler signals quickly and effectively, so that the signal to noise ratio is improved and the useful signal is obtained. In addition, the method is helpful to find required Doppler frequency shift more accurately, and the hierarchical threshold de-noising effect in wavelet threshold de-noising method is better than the global threshold de-noising effect.